Spawn for crunchy, nutty Chestnut clusters that store well after harvest.

  • Pholiota adiposa, 5 lb of fully colonized millet-blend spawn
  • Spawns 12–13 bags of 5 lb Master's Mix at about 1:3
  • Fruits cool, at 50–65°F
  • Intermediate; best on supplemented sawdust or Master's Mix
  • Ships same or next business day
Retail: $34.99
Price: $28.99
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    Item #: CMGS
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    Chestnut Colonized Grain Spawn, 5 LB Millet Bag (Pholiota adiposa)

    Chestnut Colonized Grain Spawn, 5 LB Millet Bag (Pholiota adiposa)

    Price: $28.99

    Chestnut grows clusters of golden-brown caps with a crunchy texture and a sweet, nutty flavor. Unlike delicate oysters, it keeps well after harvest, which makes it a practical choice for market and restaurant sales.

    • P. adiposaSpecies
    • ~5 lbColonized grain
    • 50–65°FFruiting temp
    • IntermediateSkill level
    • 12–13Master's Mix bags

    Why grow Chestnut from our spawn

    Stores well

    Holds up after harvest far better than delicate oysters.

    Cool-room grower

    Fruits at 50–65°F.

    Great texture

    Crunchy, with a sweet, nutty flavor.

    From bag to block

    1Break it up

    Squeeze and massage the sealed bag until the grain separates into loose kernels.

    2Set up clean

    For a simple Master's Mix spawn, a clean room with still air works. For grain-to-grain or other open work, use a flow hood.

    3Spawn about 1:3

    Roughly one part spawn to three parts substrate, or about 2 cups per 5 lb bag of sterilized Master’s Mix. One bag covers 12–13.

    4Seal and wait

    Seal the bags, mix thoroughly and let them colonize at 65–75°F before moving to fruiting conditions.

    Chestnut grain spawn specs

    SpecDetail
    Scientific namePholiota adiposa
    MyceliumWhite to pale tan
    GrainMostly white and red millet with a little milo
    BagUnicorn 3T, 3-mil, 0.22-micron filter patch
    Sterilization3-hour autoclave cycle
    Weight5 lb net; bags usually fill to about 5.5 lb
    Spawn rateAbout 1:3; one bag spawns 12–13 bags of 5 lb Master's Mix
    Best substratesSupplemented hardwood sawdust, Master's Mix
    Fruiting temperature50–65°F
    Skill levelIntermediate
    TypeGourmet
    Shelf lifeBest within about 90 days; up to 120 days refrigerated at 35–40°F
    ShipsSame or next business day

    Grow it outPair it with sterilized Master’s Mix (5 lb) or mix your own from Master’s Mix pellets. For bigger runs, stock up on Unicorn 3T filter-patch bags, and keep open work clean with a Bonsai laminar flow hood.

    Start further backPrefer to make your own spawn? Begin with a Chestnut liquid culture syringe or a colonized Chestnut agar plate. Browse every species in colonized grain spawn.

    Where our genetics come from

    Our master culture collection is the product of years of isolation work in our Illinois lab. We've added to it through a partnership with a leading commercial culture supplier in Canada and with select strains from the UK and Asia. Every culture is kept as first-generation commercial genetics and chosen for clean, vigorous colonization and fruit that's true to type.

    Common questions

    What temperature does Chestnut fruit at?

    It prefers cooler conditions, 50–65°F.

    Why choose Chestnut for selling?

    It stores well after harvest, so it travels to market and restaurants better than delicate oysters.

    How long will the spawn keep?

    Use it within about 90 days for the best results. Refrigerated at 35–40°F, it can last around 120 days.

    Do I need a flow hood?

    Not for a basic Master's Mix spawn in a clean, still room. For grain-to-grain expansion or other open work, use a flow hood or clean room.

    What if the bag arrives damaged or contaminated?

    Every bag ships fully colonized and is inspected first. If something's wrong, contact us within 5 days of delivery with a photo and we'll send a free replacement.

    Made fresh, shipped fast

    Each bag is sterilized for 3 hours in an autoclave, inoculated under HEPA-filtered laminar flow and left to colonize completely in a dedicated clean room, then inspected before it ships. Millet's small kernels mean more inoculation points per pound, so the spawn spreads quickly and evenly through your substrate.

    We produce on a rolling schedule instead of stockpiling, so your spawn is fresh. It usually ships the same or next business day in padded packaging, with a free cold pack from May through September or for hot destinations.

    Chestnut grain spawn bag beside a cluster of Chestnut mushrooms
    Chestnut spawn, fully colonized
    Hands holding broken-up colonized grain spawn
    Broken up and ready to spawn

    When it arrives: Break up the grain and spawn it soon. If you can't use it right away, refrigerate it at 35–40°F.